I asked this question at Rails Of USA and Jeff could not give me a good answer so I will miss spell it here. I have around 10 12 wheel drive Athearns older ones. Around 5 have been up dated with motor’s from the current Athearn Super Weight F-7’s motors.
What I don’t get is the stock Super weight F-7’s has a lower power draw, higher to speed and will pull more than the up grade 12 wheel drive engines? This is hauling a train and running so low as well.
Give you a idea, F-7 is hauling 26 cars and SD-45 is hauling only 7 car’s and they are pretty much even in speed? Both have the same motor?
All the older Blue boxes have been pulled a part, cleaned and lubed as well. Some have been hard wired as well!
The Athearn 3-axle flexicoil trucks have a HUGE 45-tooth idler gear in the truck tower which transfers rotation from the worm to the truck gears, and I’m thinking that big gear slows things down.
In contrast, the Athearn 3-axle HTC trucks and 2-axle Blomberg trucks have smaller 23-tooth idler gears, so I’m thinking the locos equipped with those would go faster.
I’ve sold all of my blueboxes except for a couple of U-Boats and several FP45s. The 4 axle U-Boats will out run my cowls. The difference is slight but still noticeable. Just out of curiosity I will check out the gears next time I pull the drives apart.
More gears = more friction
More axle bearings = more friction
You also don’t say how old, but if the FP45s are old enough to have the old sinistered iron wheels and outside bearing trucks, that ccan cause more electrical resistance and more friction.
Now here’s the kicker: My Blue Box FP45s from the 1970s with the old amp eating,“rocket motor” and steel flywheels will out run my late 1990s Blue Box FP45s with the newer style motor and brass flywheels. These puppies sound like a heavy duty electric pencil sharpener lol [:P][(-D] !!
I was planning on upgrading all of them with Mashima motors, but now with Athearn’s intent of producing Genesis FP45s, I think I’ll just mechanically upgrade the units from the 1990s since they they have better truck assemblies and truck detailing.
Long Island Tom is right. The gearing in the SD45 is taller than the gears in the F7. At the same RPM the taller gears will propell the SD45 at a slower speed than the F7. Bet the SD45 can pull more than the F7!
I have thought for some time that it must be in the grear ratio, plus I did wonder about the fraction of the extra gears as well.
As far as the pulling power, only engines that I have that will out pull the Super Weight is my PK’s. My SD’s, GE-C and FP 45’s have not had any weight added to them yet. On my 2% grade max my 12 wheelers will pull single headed is12 cars thats about all they will pull. Now that is with poor rolling stock, I just finaly started tuning the trucks of the rolling stock and has helped alot. With the tunned cars the F-7 is pulling 26 cars and pretty sure it will do 30 at this point.
On up grading the motors, what should I expect as far as performances? I know lower power draw, but higher RPM’s that would = more top speed? From what I have seen the cost of up grading it is all most not worth the cost. Motors around $32.00, is that right?
Ken, it’s almost certainly the weight difference. The gearing would only govern the speed at a given motor rpm. The Super-Power f-7’s are stuffed full of weight, where the 12–axle SD-45’s aren’t. If you add weight to the SD45’s until they are as heavy as the F-7, the 12-axle unit should pull slightly better up a grade.
This is A-typical of Athearn BB engines. (They almost always ran at the same speed) because they had few production and design changes over a 50 year period. It sounds like you have an assortment of BB Athearn’s from over the years that you bought used.
Their earliest (Globe) period were balky gear drives and ‘scooter’ rubber band drives. Run them inividually -while they still work- or trash them.
Better were drives with electrical pickup from outside (metal) sideframes, and followed by ones with axle pickup via bronze oilite bearings. My ALCO PA’s have both (and run together).
I THINK what you have is an assortment of engines that were never designed to run together. I KNOW about 4 different chassis and at least 3 different motors that appeared in the same F-7, GP-7, and SD-45 shells. Even their ‘best’ chassis (with THE oilite bearings) was sold with 3 different motors at different times. EASIEST solution is to replace with the same motors.
Since you feel the $32 cost of motor upgrading “is not worth the cost” I suppose an $80 new drive, is out of the question. Too bad. I’m happy with mine. A chassis with the same gearing and motor -that fits your shells- solves all.
I noticed a few people here said the larger gear in Athearn 6 axle trucks will lower the speed. They actually have no affect on the engines speed, because the worm will move the gear teeth at the same speed, and that speed is directly transfered to the axle gears, giving all Athearn BB diesels (after the “tower” and rubber band drives) the exact same gear ratio. If they had Ernst regear kits in them, that would slow them down, because the Ernst regear kits have a double gear with a smaller gear attached to a larger gear that slows down the rest of the gears.
So any speed difference that might be in the engines is caused by different motor RPM or tight mechanisms.
Hi ken, I have managed to get some Athearn locos that were new and the motors just weren’t any good. I usally have a spare around so I just swap it out. As far as pulling goes you should be able to pull more with a 12 wheel Athearn loco than almost any other including Kato. You should check to make sure the gears have no spurs, I anywhere even on the sides, make sure the motor is properly alighned, test everything before putting it back together for fit and finish…Clean the armature of each motor with an eraser. Sometimes the gears rub against each other so check them running without the wheels in the trucks. I have always been able to get good performance from these locos. Try and dig a little deeper. Good Luck!
Absolutely! The more a BB unit is ran the loser it becomes and the drive smooths out and runs quieter.Of course that can apply to any brand of locomotives but,the BB’s seems to improve from this the most…
Boy right now I miss the old format of the site. That way I could re read all the answers and answer them as I go.
New Athearn motor I am using is a 84040, at $9.95 a pop at K-10 train and the same motor in the Super Weight I figured it would be a good up grade. Even cleaned up the 12 wheelers could not touch the F-7 Super Weight. I have open all the trucks, cleaned, lubed , clean the arms (where armater contacts the brushes) and hard wire a few so there is no contact strip.
Yes, I bought all the 12 wheelers used of E-stupid, and I am sure there is a big spread in the years and miles that are on them. Few had the big round motor with steel flywheels. Some have all there details but some do not. So sticking $30.00 into them does not seem like a good idea. As far as $80.00, might as well get new PK’s.
As far as the pulling power of the 12 wheelers, wwhen I said 12 was the max I did leave out at that point I still had some LL track that up the grade to around 5% at the joining section. After the engine cleared that part shortly there after wards is when they lost traction with 12 cars. I must added the rolling stock was all so stock cheap LL and Bachman. Up graded they come close to Athearn cars I have now. I am sure they would fair much better now.
On far up grades, I was thinking a aftermarket motor.
With all the knowing people that have taken there time to answer I will trow in a second question. My SDP brass flywheels are slipping on the Arm of the motor.I have used testor glue two time, first time it started slipping after around 4 hours and 10 car’s. Did it again but keeping the load light. Short of a Keyway or a set screw any ideas?
I’ve had the same problem with some of my Athearns. I like to tear a 1/3" x 1/3" square out of a sheet of regular tissue paper (like Kleenex tissues), place it on the hole of the flywheel where the shaft will go, and press the shaft in the hole. Excess that’s sticking out can be torn out with tweezers or needle-nose pliers. After that, the flywheels stay on nice and tight, and can be taken off fairly easily later.[:D]
Loose flywheels are a result of usage. Most flywheels are press fits. A-Line sells ‘Flywheel cement’. Athearn uses motors suseptable to vibration, which exacerbates the problem.
Hobbytown chassis is a big improvement. The PPW chassis is even better.
Ken,Here is A-Lines website.Look it over and when you go to your LHS you will have a fairly good idea of what you need…Its NOT the cheapest route to take.
Just a small up date, I have ran the 12 wheeler SPD 40 with the new motor with the board up graded. With the lack of LL lock track and up grade cars it pulls very well. Hauled 30 cars with out a hich, sure beats the 12 cars it used to haul. Board was all so up graded with 22 and 26 inch turns when it hits max grade.
Have it doubled headed with a GEC 30 C and pulling 35 cars. Getting ready to push my luck with 40 caars. Old record was 36 then string effect took over. Hope the new turns and up graded stock will pay off. Wish me luck, I hate playing 52 Pick Up rather it cards or Rolling Stock.